1. Field of the Invention
The present invention relates to a nonflammable glycol-based cleaning solvent which is used such as for removing flux from electronic parts, and for cleaning ink, adhesives and other such oils and fats.
2. Description of the Related Art
Glycol-based cleaning solvents are a new type of cleaning solvent which are known to be alternatives to the conventional cleaning solvents containing chlorine or fluorine. These glycol-based cleaning solvents consist mainly of low-toxic, highly-safe propylene glycol-based solvents, and are known to be eco-friendly and less harmful to the earth's ozone shield compared to chlorine/fluorine-containing cleaning solvents. Not only do the glycol-based cleaning solvents have a high KB (kauri-butanol) value and have a good cleansing ability, they scarcely affect plastics and rubber. Therefore, they are particularly used for removing flux from electronic parts, as well as for cleaning ink, adhesives and other oils and fats.
However, almost all propylene glycol-based solvents, which are the main ingredients of the glycol-based cleaning solvents, are flammable substances and classified as hazardous materials. Thus, not only is the management of these solvents strictly regulated under fire-protection law, the amount permitted for storage/equipment is also limited, making these cleaning solvents hard to handle. Therefore, considering that second- and third-class petroleum products (a classification according to Japanese fire-protection law; second-class petroleum products have a flash point ranging between 20.degree. C.-70.degree. C. (at 1 atm), and third-class petroleum products have a flash point ranging between 70.degree. C-200.degree. C. (at 1 atm)) are not so strictly regulated under law, the glycol-based solvents used for cleaning solvents were selected from these two groups. Nonetheless, the cleaning solvents containing glycol-based substances were still classified as hazardous materials, and thus, there existed inconveniences in safety and handling.